In a typical display device such as an organic EL display device, a plurality of light-emitting elements are arranged in a display region of an element substrate.
Light-emitting elements, including organic EL elements, deteriorate easily due to moisture and oxygen entering from the outside. In Patent Literature 1, for example, deterioration of the light-emitting elements is prevented by providing an opposite substrate located opposite an element substrate, and sealing the light-emitting elements with a sealing resin layer located between the element substrate and the opposite substrate.
One method used as a method for joining the element substrate and the opposite substrate together via the sealing resin layer is a method of superimposing the element substrate, the opposite substrate, and a liquid sealant or a sheet thermoplastic sealant so that the sealant is located between the element substrate and the opposite substrate, and curing the sealant.
As disclosed in Patent Literature 2, curing of the sealant is initiated by heat or UV light irradiation, for example.